I have been very satisfied with the two Dell Precision Workstation (laptop) computers I purchased. Both have proven to be real workhorses and neither has resulted in any significant problem. I use both for design and condoc work and to a lesser degree for presentation (rendering). The units I own were purchased several years ago and the Precision line has incorporated quite a few embellishments since then.
These computers can be built to suit your taste and budget and I think they can be obtained at a purchase price south of $3000.00.
[EDIT]: I recall taking delivery on each of the orders within 30 days of making the purchases during which period the units were assembled to the specs I agreed to. I should also emphasize that the support I have received from Dell has been second to none. I have been able to speak to technical representatives with any questions that arose when I was acclimating to one system or the other and although I have not had to take advantage of their service policy, Dell provides an option for a tech support person to actually come to your location and provide next day service as required. The warranty period may be extended beyond one year for a reasonable upgrade cost (as I recall it was around $100.00 for 3 years, but don’t quote me on that figure).
Of course defining the “BEST” computer is highly subjective and opinions will vary wildly as what I consider best may be viewed as marginal by someone else.